In a padded rehearsal room in the backstreets of Brunswick, in Melbourne's inner north, the yo ung women of Milk Crate are not-so-quietly upending the patriarchy.

It's a school night, so they do so before their 8:30pm pick-up. But in their brash, guitar-driven "beach goth" (their term) music, influenced by bands with female members like The Pixies and Bikini Kill, you can see change coming.

But it's not just change in the music business, which is currently engaged in a protracted discussion about ingrained sexism.

The story of Milk Crate's significance â" if you can say that about a band of 14- and 15-year-olds who have played just one show â" is the story of the guitar itself.

The idea of the guitar hero is changing

Guitar sales are still strong â" it's the defining instrument of modern popular music, after all â" but there are problems afoot.

The instrument has long appealed to men, sparked by the postwar birth of rock 'n' roll and its virtuosic (and often male) stars like Jimi Hendrix and Eri c Clapton.

Now, as even Clapton has acknowledged, a younger generation who has grown up with hip-hop in the charts and Ableton programming software on their laptops are not as readily embracing the fretted instrument.

That has led to a lot of deep thinking on the part of guitar makers â" including Gibson, which is currently mired in bankruptcy proceedings â" and the answer seems to be this: find a new market.

That market is women.

"Fender commissioned its first meaningful research on new guitar buyers in 2015 with a singular focus on the US, and discovered that 50 per cent of new players in the US were women then," CEO of American guitar maker Fender, Andy Mooney, told the ABC.

This week, the company released updated research, conducted on its behalf by a consultancy called Egg Strategy using a representative sample of beginner players.

"The 50 per cent trend has continued in the US and the same trend is evident in the UK," Mr Mooney said.

"We don't have hard data on Australian players just yet, but I'd speculate that the same would hold true."

Frankie Harvey, 14, and Beth Jackson, 15, who both play guitar in Milk Crate, came to the instrument recently via their involvement with Girls Rock! Melbourne, which runs workshops and holiday programs for aspiring female, trans and gender-diverse musicians.

"They're really versatile, easy instruments to play," says Beth.

Frankie was influenced by a family friend, who played in the Australian band Real Life, but struggled to stick with guitar lessons.

"So, when the opportunity with Girls Rock! arose I was like: that's a good opportunity," she says.

What's this got to do with the music business?

The music industry has a similar problem to the one facing the market for guitars: it's a boys club.

Several festivals, including Falls and Jumanji, have been dragged publicly in the past few years for not programming enough women in high-profile slots. (There is even an Instagram account dedica ted to this trend.)

Meanwhile, the majority of the acts to make it into the triple j Hottest 100 over the past 10 years have been male.

Photo: Jimi Hendrix plays his Fender. (Amalie R RCS/CM: Reuters)

That's why people like Perth musician Stella Donnelly â" who has been unafraid to tackle gender dynamics on songs like Boys Will Be Boys â" reckon the fact more young women are getting into the guitar is good news.

"You can't be what you can't see," Donnelly, currently touring the US, tells the ABC down the phone from â" of all places â" Nashville, where Gibson has its headquarters.

"When I was going to festivals as a young girl, there would only be m aybe three women up there playing guitar that I would look up to.

"And I really focused on those three women so that really inspired me to buy a guitar and get that happening.

"But I guess it is a sign that more women are playing festivals and there is more exposure for female and LGBTQI artists out there, so it's inspiring young people to buy guitars and get into it."

There is more to the guitar than the stage

Fender's research also looked at what new guitarists wanted out of their involvement with the instrument. For the majority, it was not rock superstardom, but a sense of identity.